Conveyor belt cleaner scraper blade with sensor and control system therefor

Abstract

A conveyor belt cleaner scraper blade for cleaning the surface of a conveyor belt and a method of manufacture of the scraper blade. The scraper blade includes a body having a base member adapted to be attached to a cross shaft of a conveyor belt cleaner and a scraping member which extends outwardly from the base member to a scraping tip. The scraper blade includes one or more electrical sensors that are embedded in an insert member. The insert member and the sensors are molded and embedded within the body of the scraper blade. Each of the sensors is adapted to provide an electrical output signal representing a physical condition of the scraper blade sensed by the sensor. A variety of sensor embodiments are described, as well as two embodiments of control and monitoring systems for use in conjunction with the various blade and sensor combinations.

1. A method for controlling a conveyor belt cleaning system having a conveyor belt cleaner scraper blade disposed on an associated cross shaft, the method comprising the steps of:
 (a) monitoring output signals from a plurality of sensors disposed about the cross shaft, including a blade wear sensor and a strain sensor coupled to the scraper blade;  
 (b) computing angle of attack of the scraper blade with respect to the conveyor belt based upon radial displacement and blade wear sensor signals;  
 (c) determining current system performance based upon measured sensor signals; and  
 (d) adjusting scraper blade angle of attack and blade engagement force.  
 
   
   
     2. The method in accordance with  claim 1  including the step of determining initial linear and angular displacements of the cross shaft with respect to the conveyor belt. 
   
   
     3. The method in accordance with  claim 1  wherein the step (a) of monitoring output signals from a plurality of sensors further comprises the steps of establishing a sampling duration and a sampling interval, inputting a data snapshot through a multi-channel ADC, time stamping the data snapshot, and storing the data elements of the data snapshot in memory. 
   
   
     4. The method in accordance with  claim 1  wherein the step (b) of computing angle of attack comprises the steps of establishing the radial distance of the scraper blade pivot axis from the conveyor belt, deriving scraper blade length from wear sensor signals that define a range of possible length values, and computing angle of attack using geometric analysis. 
   
   
     5. The method in accordance with  claim 1  including the step of empirically determining a model of optimum system behavior by analyzing strain sensor data indicative of scraper blade deflection during verified normal operation, along with data indicative of scraper blade radial displacement and scraper blade engagement force. 
   
   
     6. The method in accordance with  claim 1  wherein the step (c) of determining current system performance comprises the step of comparing measured strain sensor output signals with their predicted values based upon a model of optimum system behavior. 
   
   
     7. The method in accordance with  claim 1  wherein the step (d) of adjusting scraper blade angle of attack and blade engagement force to optimize current system performance comprises recalculating blade angle of attack based upon current blade wear sensor data and cross shaft radial displacement data, then repositioning the cross shaft and adjusting scraper blade engagement force as required.